Fuses are commonly-used in various products to protect electrical components and wiring from receiving unintended high levels of electrical current that could otherwise damage the protected components and wiring. In particular, fuses are positioned in electrical circuits between the power source and the component or wiring to be protected. When a fuse experiences an electrical current level that exceeds a threshold current (rated for the particular fuse), the fuse “blows,” thereby disconnecting the power source from the protected wiring or component. Thus, the protected component or wiring is protected from the unintended high current level.
Many electrical distribution centers, such as those used for motor vehicles, utilize loose-piece replaceable fuses to protect electrical components and wiring. These replaceable fuses come in various sizes with various current-handling capabilities and are typically chosen based on the current-carrying requirements of the circuit they are intended to protect. They are typically installed between two terminals in a system in an accessible location. If such a conventional serviceable fuse blows in the field, it is may be replaced with a similar fuse by a consumer or service person, such as, in the case of motor vehicles, a mechanic in a garage. Examples of replaceable fuses may be found in U.S. Pat. No. 5,346,411 entitled “Tap-In Blade Fuse”; U.S. Pat. No. 2,527,160 entitled “Plug Type Fuse”; and U.S. Pat. No, 3,581,262 entitled “Safety Fuse With Glass Coating On Fusible Portion.” Such replaceable fuses offer the advantage of being readily available to the consumer or the mechanic at the time that a replacement is needed. When replacement fuses are in an accessible location, they are readily removed and replaced and are therefore referred to herein as “serviceable fuses.”
As an alternative to the above-described serviceable fuses, some electrical distribution centers use non-replaceable or “non-serviceable fuses” to protect electrical components and wiring. Non-replaceable fuses are commonly integrated onto circuit boards during manufacture and cannot be replaced or serviced without replacing the entire circuit board. Examples of non-serviceable fuses may be found in United States Patent Application Number 2005233515 entitled “Method Of Etching A Semiconductor Device”; United States Patent Application Number 2003205777 entitled “Integrated Fuse With Regions Of Different Doping Within The Fuse Neck”; U.S. Pat. No. 5,552,757 entitled “Surface-Mounted Fuse Device”; U.S. Pat. No. 5,923,239 entitled “Printed Circuit Board Assembly Having An Integrated Fusible Link”; and German Patent Number 3,723,832 entitles “Printed Circuit With An Integrated Fuse.” Other “non-serviceable fuses within the meaning of this disclosure include fuses that would otherwise be replaceable but for their physical location in the system (i.e., fuses that are positioned in inaccessible locations).
While serviceable fuses are conveniently replaceable, they can represent a significant cost to the manufacturer of the original product in comparison to the use non-serviceable fuses. A serviceable fuse is more costly to manufacture than a non-serviceable fuse. Further, a serviceable fuse must be physically installed, either manually or by machine, in the terminals in the electrical distribution center assembly, thereby adding additional steps and costs to the manufacturing process. Even where the installation is accomplished automatically, various steps in the automated process, such as manual loading of the supply tubes for the automatic insertion equipment, must still be performed manually. On the other hand, non-serviceable fuses are less costly to manufacture and they do not require any special handling or fixturing. However, when such a non-serviceable fuse blows, it is not possible for a mechanic or consumer to rapidly and inexpensively replace the fuse alone. Instead, the entire device or a circuit board (on which the non-serviceable fuse resides) must be replaced when a non-serviceable fuse blows. Thus, it is significantly more costly to replace a non-serviceable fuse (i.e., replace an entire circuit board) than to replace a serviceable fuse.
As a result, a dilemma exists in designing fuses into electrical systems. It may be advantageous to a manufacturer to choose a non-serviceable fuse instead of a serviceable fuse at the time of manufacture to save manufacturing cost. However, it may be disadvantageous to have a non-serviceable fuse rather than a serviceable fuse at the time that a repair is needed, since the repair will be more expensive. Thus, the choice of a non-serviceable fuse may increase warranty cost and consumer dissatisfaction. Hence, in retrospect, if the fuse never blows, a non-serviceable fuse is more cost effective, but if the fuse blows during the lifetime of the electrical system, a serviceable fuse is more cost effective.
The embodiments disclosed herein are intended to address this dilemma. Further areas of applicability of the present invention will become apparent from the detailed description provided herein. It should be understood that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are intended for purposes of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.